Rock excavation or scaling projects are often performed near a flow of traffic, for example, on a highway. Normally, these activities require that traffic be stopped in order to safely proceed with the work. Another alternative is to detour the traffic around the site of the rock excavation or scaling.
The subject invention provides a modular rock fall protection device, a modular rock catchment barrier, which permits all the normal range of construction activities found on a rock excavation or scaling site to be carried on virtually unrestricted directly adjacent to traffic, while also providing a time-proven traffic safety barrier. Since the catchment barrier can be installed prior to any work and remain in place throughout the progression of the blasting, it must also be strong enough to prevent moderate sizes of shot rock material from reaching the roadway during blasts. The subject invention can also be used as a semipermanent or permanent modular rock fall protection device where there is a need to protect an area from rocks falling from a rock face, where no rock excavation or scaling is occurring.
The subject invention thus provides a new type and level of protection in these rock excavation or scaling sites, and to protect near rock faces. The advantages of the subject invention are best illustrated by examining the types of rock fall protection devices in the prior art.
U.S. Pat. No. 4,335,868, issued June 22, 1982 to Ribbert discloses an avalanche fence consisting of uphill and downhill catchment nets or planks attached to spaced apart supports having an inverted U shape, with the ends of each U inserted into holes in the ground either directly or by mounting on pins projecting from the ground.
U.S. Pat. No. 4,730,810, issued Mar. 15, 1988 to Rambaud discloses a protective barrier for containing rock falls on sloping ground. The barrier comprises a sheet of netting held spread out upright by spaced apart posts. Each post is held upright by uphill and downhill stays on a guide formed by an endless cable looped around uphill and downhill pulleys. A mooring cable equipped with a shock absorbing means is connected to each cable loop to permit controlled downhill displacement of the post on the guide when the netting or the posts are struck by falling rock units.
U.S. Pat. No. 2,813,197, issued Nov. 12, 1957 to Hubbard et al. discloses signal wires strung between an end post and an intermediate post which are protected from falling rocks by a litter trap comprising a wire mesh extending between frame members. Each frame member is pivotally connected at its lower end to a post or is held at an angle to the post by a bar.
Various types of fence structures are also disclosed in the prior art which are not constructed to protect against rock falls.
U.S. Pat. No. 2,709,073, issued May 24, 1955 to Dougherty discloses a fence composed of prefabricated wire screen panels carried by spaced apart corner posts and line posts. The posts are mounted in sleeves set in grout. Each wire screen panel has a frame structure of horizontal top and bottom sails and vertical side rails. Mounting rings welded to the respective vertical side rails slideably connect each panel to two successive posts.
U.S. Pat. No. 1,012,868, issued Dec. 26, 1911 to Laney discloses a fence assembled from precast concrete panels. Each panel has along its lower edge transverse bars terminating in deepening lugs or feet which can be imbedded in the ground to anchor and support the panels upright. To assemble a fence, the panels are placed end to end with successive panels being hinged together by coupling pins inserted through eyes at the ends of the panels. Spaced posts embedded in the panels extend from the upper edges of the panels and support an upper rod with a strand of barbed wire.
U.S. Pat. No. 4,685,656, issued Aug. 11, 1987 to Lee et al. discloses a racetrack barrier assembled and surmounted by a weldmeshed fence. The weldmeshed sheets are connected to posts set in sleeves disposed in vertical grooves at the ends of the barrier modules.
Thus, it is readily apparent from the types of fences and catchment barriers disclosed in the prior art that there is a need for a modular rock fall protection device that would permit all the normal range of construction activities found on a rock excavation or scaling site to be carried on virtually unrestricted directly adjacent to traffic, while so providing a time-proven traffic safety barrier. There is also a need for a modular rock fall protection device in semi-permanent or permanent sites to protect an area from rocks falling from a rock face, where no rock excavation or scaling is occurring.